From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14511 invoked by alias); 10 Sep 2010 19:23:27 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 14501 invoked by uid 22791); 10 Sep 2010 19:23:26 -0000 X-SWARE-Spam-Status: No, hits=-6.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Date: Fri, 10 Sep 2010 19:23:00 -0000 From: Oleg Nesterov To: Roland McGrath Cc: Jan Kratochvil , utrace-devel@redhat.com, archer@sourceware.org Subject: Re: gdbstub initial code, v7 Message-ID: <20100910192001.GA30490@redhat.com> References: <20100830185850.GA1132@redhat.com> <20100830192040.GA15431@host1.dyn.jankratochvil.net> <20100831072048.GA26362@host1.dyn.jankratochvil.net> <20100902200632.GA23692@redhat.com> <20100903064008.GA16249@host1.dyn.jankratochvil.net> <20100903230957.GC8917@redhat.com> <20100910101452.39015405D5@magilla.sf.frob.com> <20100910182903.GB27699@redhat.com> <20100910190547.85CBD405D5@magilla.sf.frob.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100910190547.85CBD405D5@magilla.sf.frob.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SW-Source: 2010-q3/txt/msg00180.txt.bz2 On 09/10, Roland McGrath wrote: > > > ugdb sets "please stop" flag and does utrace_control(INTERRUPT). However, > > in unlikely case the tracee can stop before ->report_signal() reporting > > I don't think this is the right thing to do. When the intent is explicitly > to interrupt, there is no reason to stop before the interruption is > complete, i.e. report_signal. This means that ugdb_report_quiesce() should never return UTRACE_STOP, and that is all. But what about multitracing? Suppose that "(gdb) interrupt" happens just before, say, do_report_syscall_entry() and another engine wants to stop. If ugdb_report_quiesce() doesn't return UTRACE_STOP, then gdb will wait until another debugger resumes the tracee. What do you think? > If you only stop there, then you can always > process a signal injection with complete flexibility. Yes, sure (again, currently ugdb does not injection a signal even if the tracee was stopped in report_signal, but of course we can change this). Oleg.